1. Field of the Invention
The subject invention generally relates to cells in a battery pack, and more particularly relates to a method of deactivating faulty or bad battery cells from a battery pack for use in an electric vehicle or other industrial equipment.
2. Description of Related Art
Battery packs have been used for numerous years in electric vehicles, such as automobiles, boat, aerospace vehicles, and within other industrial equipment applications. Many of the electrical systems used in these prior art vehicles and equipment are designed to minimize the possibility of short circuiting and to reduce the potential of a voltage exposure to emergency responders and other people in the general public. Such precautions may help to reduce the possibility of an electrocution or other injury due to high voltage encounters and situations. There have been many different attempts at providing an electrical system that will disconnect electrical circuits due to a crash of a vehicle, high temperature situations or other short circuit that may occur in a vehicle or industrial equipment. Many of these prior art systems would disconnect the battery from the circuit thus creating an open circuit and protecting any responders and other people from dangerous high voltage situations. Generally, these prior art systems disconnect the battery pack when a predetermined force is applied to the vehicle or equipment or when a predetermined thermal event occurs within the circuitry of the battery and or electrical system.
One of the prior art methodologies for disconnecting battery cells would use a conductor wire that is either welded or bonded to a battery cell and is capable of being broke if a mechanical force is applied thereto. In the prior art, one problem with these prior art systems is that the mechanical strength of the breakable conductors may be excessive and not allow for the conductor to break unless it is subject to extreme forces or situations with relation to the vehicle or equipment. Therefore, the disconnecting of the power from the supply of the electric vehicle may not occur during all emergency situations as originally designed and would not occur for short circuits that may effect the storage capacity of the battery cells and the longevity and durability of the battery cells for holding a charge. Furthermore, many of the prior art methodologies of wire bonding conductors to cells did not provide a consistent connection. Current mechanisms such as high thermal events may not break the conductor thus leaving the equipment connected to the circuits power which may result in electrocution and injury to first responders at an accident scene. Some of these prior art methodologies may also have tried insulation displacement conductors to connect a battery cell to a bus bar or connector plate, mechanical crimping or pressure crimping may also have been used to connect battery cells to a bus bar. Furthermore many of these prior art systems would only disconnect during a vehicle accident or hard short circuit but would not disconnect battery cells suffering from internal weak shorts or problematic weak shorts during charging or use within a battery pack environment.
Therefore, there is a need in the art for an improved methodology of deactivating a faulty or bad battery cell from a battery pack in an electrical vehicle or industrial equipment. Furthermore, there is a need in the art for a methodology that will be capable of detecting which individual cell has a weak short circuit, problematic weak short circuit and thus isolate or remove the bad cell from the electrical circuit. Also there is a need in the art for a low cost manufacture methodology and apparatus for deactivating faulty or bad cells from a battery pack in an electric vehicle.